Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 240925 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 525 AM EDT SUN AUG 24 2014 .SYNOPSIS... HIGH PRESSURE WILL BUILD FROM THE NORTHEASTERN STATES DOWN THE COAST...REACHING THE DELMARVA TONIGHT...AND REMAINING THROUGH MIDWEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... LTST SFC ANALY DEPICTS HIPRES WEDGING DOWN THE EASTERN SEABOARD INTO THE CWFA. SNDGS...BOTH OBSVD 00ZLWX AND AREA PROGS...SUGGEST THAT LYR OF ELY FLOW EXTENDS FM SFC THRU ABT H7...W/ N/NWLY WNDS ABV THAT. THE ONSHORE LYR SUFFICIENT TO PROVIDE LOW CLDS/DZ TO THE AREA. DRYING ALOFT MAKING IT LESS LKLY TO RECEIVE ADDTL LARGER DROPLET PCPN. HV RETOOLED WX GRIDS TO AREAS DZ W/ CHC/SCHC RA THRU MID MRNG...CONCENTRATING ON ERN UPSLP AREAS. MAY BE SOME FOG TOO...THO SUSPECT GDNC PROGS DISPLAYING TYPICAL BIAS OF OVERDOING IT. AS SUBSIDENCE OVERTAKES AREA...IT WL BECOME INCRSGLY UNLKLY TO EVEN SEE DZ...AS CLDS WL BREAK FM NE TO SW. SHUD HV A MOSUN AFTN JUST ABT EVERYWHERE. GDNC WAS TOO WARM YDA...BY QUITE A BIT. PRVS FCST WAS HIER THAN GDNC MEAN FOR MAXT TDA. LWRD TO MATCH CONSENSUS. && .SHORT TERM /6 PM THIS EVENING THROUGH MONDAY NIGHT/... HIPRES WL BE DOMINATING WX FEATURE SFC AND ALOFT THRU MON NGT. THE SFC RDGG WL EMINATE FM THE NE. H7-5 RDGG WL COME FROM THE LARGE DOME TO OUR SW. THIS TAG TEAM SHUD MEAN MOCLR NGTS AND A SUNNY OR MOSUN DAY MON. THE DIURNAL FLOW WL STILL BE ELY...BUT XPCT DCPLG EACH NGT. MON MAXT MAYBE A CPL DEGF HIER THAN TDA. AS DEWPTS DROPPING BLO 60F...HV DONE LIKEWISE TO MIN-T OUTSIDE OF THE CITIES EACH NGT. && .LONG TERM /TUESDAY THROUGH SATURDAY/... AN EXPANSIVE UPPER LEVEL RIDGE WILL BE IN CONTROL ACROSS MUCH OF THE SOUTHEASTERN US TUESDAY. HIGH PRESSURE WILL BE AT THE SURFACE LEADING TO DRY AND CALM CONDITIONS THROUGH MIDWEEK. TROPICAL DEPRESSION FOUR WILL BE OFF THE FL COAST MOVING NORTHWARD DURING THIS TIME. THE TRACK OF THE DEPRESSION WILL MOVE NORTH AND THAN EAST STAYING AWAY FROM THE MID ATLANTIC COAST. WINDS SHOULD HAVE AN EASTERLY COMPONENT AS THE DEPRESSION STRENGTHENS INTO A HURRICANE AND MOVES EAST OF THE REGION THROUGH WEDNESDAY. TEMPERATURES WILL CLIMB INTO THE UPPER 80S BY WEDNESDAY. A TROPICAL SYSTEM WILL BE WELL OFF THE OBX COAST THURSDAY WHILE LOW PRESSURE NEAR LABRADOR MOVES EASTWARD. AN ASSOCIATED COLD FRONT WILL APPROACH THE MID ATLANTIC THURSDAY. AT THIS TIME FORCING IS WEAK ALONG THE FRONT. SHOWERS AND THUNDERSTORMS ARE POSSIBLE THURSDAY AND THURS NIGHT. A SHORTWAVE TROUGH WILL APPROACH THE GREAT LAKES TOWARDS THE END OF THE WEEK AND LOW PRESSURE IS EXPECTED TO DEVELOP NORTHWEST OF THE MID ATLANTIC BY FRIDAY. TEMPERATURES ARE EXPECTED TO BE IN THE UPPER 80S AND LOW 90S TOWARDS THE END OF THE WEEK. && .AVIATION /10Z SUNDAY THROUGH THURSDAY/... ON THE WHOLE...MVFR/VFR CONDS PREVAIL ACRS THE TERMINALS ATTM. LOWEST CIGS MVFR/CHO...WHERE OCNL IFR PSBL. VFR HAS BEEN MORE PREVALENT AT THE METROS...BUT IAD ON THE EDGE OF THE LWR CLD DECK /BKN010-015/. SINCE FLOW PTTN STILL ELY...LOWEST 5K FT NEARLY SATD...AND ATM STILL UNDERGOING DIURNAL COOLING...ITS NOT IMPOSSIBLE TO SEE THIS LOW CLD DECK EXPAND EWD. HWVR...DRIER AIR FILTERING SWD... AND WL BET THAT PREVAILS. THEREFORE...WL BE KEEPING VFR FCST THRU DAYBREAK UNLESS OBS DICTATE OTRW. AFTR SUNRISE...CONDS WL BE IMPRVG. SHUD BE VFR FOR MOST OF THE DAY. VFR CONTG THRU MON. ELY FLOW DURING THE DAY...DCPLG AT NGT. TUE-WED...VFR. THU...MAINLY VFR THO MAY BE BRIEF FLGT RESTRICTIONS INVOF TSRA. && .MARINE... ELY FLOW AND HIPRES WEDGING SWD FM NEW ENGLAND LED TO A PUSH OF DRIER AIR...MARKED BY 15-20 KT WNDS. THESE A BIT HIER THAN I THOUGHT YDA...BUT THE TREND PAST CPL HRS HV BEEN DOWNWARD. GNLY HV A SUSTAINED 10-15 KT BREEZE ATTM XCPT FOR 15-20 NEAR THE MOUTH OF THE BAY. GDNC SUGGESTING THATS WHERE OPPORTUNITY STILL RESIDES...AND IT SHUD BE DONE BY SUNRISE. WL HOLD ONTO SCA FOR LOWEST THREE ZONES... AND CANX ELSW. ELY FLOW WL BE MAINTAINED THRU MON NGT...10-15 KT TDA AND AOB 10 KT TNGT THU MON NGT. WNDS BCMG SLY MIDWEEK...BUT SPDS REMAINING BLO 10 KT. && .TIDES/COASTAL FLOODING...
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EAST WINDS HV BEEN DRIVING WATER INTO THE CHESAPEAKE BAY AND TIDAL POTOMAC RIVER. TIDAL DEPARTURES NOW RUNNING BETWEEN 1.0-1.5 FT ABV ASTRONOMICAL NORMS. AT THESE LEVELS...MINOR FLOOD THRESHOLDS HAVE BEEN MET...AND EXPECT THAT TREND TO CONTINUE AS THE TIDE MAKES IT WAY UP THE ESTUARY. IN THE BAY...THE ADVY EXTENDS N TO BALTIMORE. SINCE OBSERVED LEVELS MAY BE A LITTLE UNDER CBOFS GUIDANCE...IT MAY BE POSSIBLE THAT THE INNER HARBOR MAY FALL A PINCH SHY...SUGGESTING THAT THIS IS AN APPROPRIATE END POINT. ON THE POTOMAC...THE SHORELINE LESS SENSITIVE TIL THE UPPER WATERS. DEPARTURES PAST COUPLE OF HOURS HAVE INCREASED BY A HALF-FOOT. THATS ENOUGH TO JUSTIFY ADDING PG TO THE ADVY FOR DC AND ALEX. FFX HAS A MUCH HIER CRITERIA. THE FLOW PATTERN WILL NOT CHANGE FOR THE NEXT COUPLE OF TIDE CYCLES...MEANING TIDAL ISSUES WILL LINGER. THE PM TIDE THE LOWER OF THE TWO ASTRONOMICALLY. BASED ON LATEST TRENDS AND FORECAST OF CONTD EASTERLY FLOW...HAVE OPTED TO CONTINUE ADVY FOR CALVERT AND ST MARYS COUNTIES FOR THE NEXT TWO TIDE CYCLES. AM NOT AS SURE ABOUT THE REST OF THE WATERS...INCL ANNAPOLIS. EVEN IF NOTHING ELSE IS REQUIRED FOR THIS AFTN/EVENING...ITS LOOKING QUITE PLAUSIBLE THAT THERE WILL NEED TO BE ACTIVE ADVYS FOR THE MON AM TIDE CYCLE. LITTLE CHANGE TO THE OVERALL PATTERN THROUGH TUESDAY...SO WERE NOT OUT OF THE WOODS FOR TUE MORNING EITHER.
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&& .LWX WATCHES/WARNINGS/ADVISORIES...
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DC...COASTAL FLOOD ADVISORY UNTIL 10 AM EDT THIS MORNING FOR DCZ001. MD...COASTAL FLOOD ADVISORY UNTIL 5 AM EDT MONDAY FOR MDZ017-018. COASTAL FLOOD ADVISORY UNTIL 10 AM EDT THIS MORNING FOR MDZ011- 013-014. VA...COASTAL FLOOD ADVISORY UNTIL 10 AM EDT THIS MORNING FOR VAZ054. WV...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 10 AM EDT THIS MORNING FOR ANZ534- 537-543.
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&& $$ SYNOPSIS...HTS NEAR TERM...HTS SHORT TERM...HTS LONG TERM...HAS AVIATION...HTS MARINE...HTS TIDES/COASTAL FLOODING...HTS

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